Amblyopia is a visual development deficit caused by abnormal visual experience in early life, mainly manifesting as defected visual acuity and binocular visual impairment, which is considered to reflect abnormal development of the brain rather than organic lesions of the eye. Previous studies have reported abnormal spontaneous brain activity in patients with amblyopia. However, the location of abnormal spontaneous activity in patients with amblyopia and the association between abnormal brain function activity and clinical deficits remain unclear. The purpose of this study is to analyze spontaneous brain functional activity abnormalities in patients with amblyopia and their associations with clinical defects using resting-state functional magnetic resonance imaging (fMRI) data. In this study, 31 patients with amblyopia and 31 healthy controls were enrolled for resting-state fMRI scanning. The results showed that spontaneous activity in the right angular gyrus, left posterior cerebellum, and left cingulate gyrus were significantly lower in patients with amblyopia than in controls, and spontaneous activity in the right middle temporal gyrus was significantly higher in patients with amblyopia. In addition, the spontaneous activity of the left cerebellum in patients with amblyopia was negatively associated with the best-corrected visual acuity of the amblyopic eye, and the spontaneous activity of the right middle temporal gyrus was positively associated with the stereoacuity. This study found that adult patients with amblyopia showed abnormal spontaneous activity in the angular gyrus, cerebellum, middle temporal gyrus, and cingulate gyrus. Furthermore, the functional abnormalities in the cerebellum and middle temporal gyrus may be associated with visual acuity defects and stereopsis deficiency in patients with amblyopia. These findings help explain the neural mechanism of amblyopia, thus promoting the improvement of the treatment strategy for amblyopia.
ObjectiveTo observe the accuracy of magnetic resonance imaging (MRI) for predicting pathologic complete response (pCR) after neoadjuvant chemotherapy (NAC) in breast cancer, and to analyze the cause of the prediction error.MethodsData from 157 breast cancer patients who underwent NAC before surgery in Mianyang Central Hospital from January 2017 to January 2019 were analyzed. MRI parameters before and after NAC and pCR conditions were collected to analyze the parameters that produced false positives and false negatives.ResultsOf the 157 patients, 37 (23.6%) achieved pCR after NAC, and 33 (21.0%) achieved radiation complete remission (rCR) after NAC. The accuracy of MRI prediction was 70.7% (111/157), the sensitivity was 82.5% (99/120), and the specificity was 32.4% (12/37). A total of 25 cases did not achieve rCR, but postoperative evaluation achieved pCR (false positive), 21 cases achieved rCR, but postoperative evaluation did not achieve pCR (false negative). Diameter of tumor, peritumoral oedema, and background parenchymal enhancement were associated with MRI false positive prediction (P<0.05); gland density and tumor rim enhancement were associated with MRI false negative prediction (P<0.05).ConclusionMRI can be used as an important method to predict pCR after NAC in breast cancer patients, and its accuracy may be related to diameter of tumor, peritumoral oedema, background parenchymal enhancement, gland density, and tumor rim enhancement.
Brain aging can affect the strength of functional connectivity between brain regions. In recent years, studies have shown that functional connectivity is fluctuant over time, and can reflect more physiological and pathological information. Therefore, in the study resting state functional magnetic resonance imaging (fMRI) data of 32 elderly subjects and 36 younger subjects were selected, and the sliding window technique was used to estimate dynamic functional connectivity network. Then, the dependency of fluctuating energy difference on frequency band was studied using wavelet packet analysis, conducting the linear regression with age at the same time. Results showed that the fluctuating energy in older group was significantly higher than that in the young group in low frequency, and it was significantly lower than that in the young people in high frequency. These results suggested that the dynamic functional connectivity between networks in the elderly exist slow wave phenomenon, which may be related to the decreased reaction rate of the elderly. This article provides new ideas and methods for the research about brain aging, and promotes a theoretical basis for further understanding of the physiological significance of brain dynamic functional connectivity.
In order to investigate the features of multidetector CT (MDCT) and magnetic resonance imaging (MRI) as well as the corresponding pathogic basis of solitary fibrous tumor (SFT) in the pelvis, we collected the clinical data of 13 patients with pathologically confirmed SFT in pelvis, and retrospectively reviewed the MDCT and MRI appearances. Of these enrolled patients, 6 received MDCT scans, 5 underwent MRI scans, and 2 underwent both MDCT and MRI examinations. Shown on the MDCT and MRI, the maximum diameters of the masses ranged from 4.0 to 25.2 cm (averaged 11.8 cm). Six masses were lobulated, and seven were round or oval. In addition, all masses were well-defined and displaced the adjacent structures to some degrees. On the computed tomography, all masses were of isodensity on unenhanced scans in general, among which five masses were demonstrated with hypodense areas. On the MRI T1-weighted image, all lesions were isointense, of which patchy hypointense areas were detected in 3 cases and radial hypointense areas were in 3 cases, and the other one was presented with homogenous intensity. On T2-weighted images, most of the lesions were mixed hyperintense, of which 3 cases were of heterogenous hyperintesity, radial hypointense areas were detected in 3 patients, and the other one was homogenously intense. On enhanced computed tomography and MRI, large supplying vessels were found in 4 cases; 12 cases showed moderate to conspicuous enhancement, and the other one was presented with mild homogenous enhancement. Of the patients with moderate to conspicuous enhancement, patchy areas of non-enhancement were detected in 7 cases, radial areas of progressive enhancement were detected in 3 cases, and the remained 2 cases showed homogenous enhancement. On pathology, the radial area presented as progressive enhancement was fibrosis. During the follow-ups after surgery, 2 patients had local recurrence and 1 had metastasis to liver. In conclusion, the SFT in the pelvis are commonly presented as a large solid, well-defined and hypervascular mass with necrosis or cystic changes at some extents together with the displacement of adjacent structures. The radial area with hypointensity on T2-weighted image and with progressive enhancement on enhanced magnetic resonance imaging is an important feature of SFT, which can be helpful for the diagnosis of this mass.
Aiming at motion artifacts and off-resonance artifacts in multi-shot diffusion magnetic resonance imaging (MRI), we proposed a joint correction method in this paper to correct the two kinds of artifacts simultaneously without additional acquisition of navigation data and field map. We utilized the proposed method using multi-shot variable density spiral sequence to acquire MRI data and used auto-focusing technique for image deblurring. We also used direct method or iterative method to correct motion induced phase errors in the process of deblurring. In vivo MRI experiments demonstrated that the proposed method could effectively suppress motion artifacts and off-resonance artifacts and achieve images with fine structures. In addition, the scan time was not increased in applying the proposed method.
Objective To investigate the differences in the topology of functional brain networks between populations with good spatial navigation ability and those with poor spatial navigation ability. Methods From September 2020 to September 2021, 100 college students from PLA Army Border and Coastal Defense Academy were selected to test the spatial navigation ability. The 25 students with the highest spatial navigation ability were selected as the GN group, and the 25 with the lowest spatial navigation ability were selected as the PN group, and their resting-state functional MRI and 3D T1-weighted structural image data of the brain were collected. Graph theory analysis was applied to study the topology of the brain network, including global and local topological properties. Results The variations in the clustering coefficient, characteristic path length, and local efficiency between the GN and PN groups were not statistically significant within the threshold range (P>0.05). The brain functional connectivity networks of the GN and PN groups met the standardized clustering coefficient (γ)>1, the standardized characteristic path length (λ)≈1, and the small-world property (σ)>1, being consistent with small-world network property. The areas under curve (AUCs) for global efficiency (0.22±0.01 vs. 0.21±0.01), γ value (0.97±0.18 vs. 0.81±0.18) and σ value (0.75±0.13 vs. 0.64±0.13) of the GN group were higher than those of the PN group, and the differences were statistically significant (P<0.05); the between-group difference in AUC for λ value was not statistically significant (P>0.05). The results of the nodal level analysis showed that the AUCs for nodal clustering coefficients in the left superior frontal gyrus of orbital region (0.29±0.05 vs. 0.23±0.07), the right rectus gyrus (0.29±0.05 vs. 0.23±0.09), the middle left cingulate gyrus and its lateral surround (0.22±0.02 vs. 0.25±0.02), the left inferior occipital gyrus (0.32±0.05 vs. 0.35±0.05), the right cerebellar area 3 (0.24±0.04 vs. 0.26±0.03), and the right cerebellar area 9 (0.22±0.09 vs. 0.13±0.13) were statistically different between the two groups (P<0.05). The differences in AUCs for degree centrality and nodal efficiency between the two groups were not statistically significant (P>0.05). Conclusions Compared with people with good spatial navigation ability, the topological properties of the brains of the ones with poor spatial navigation ability still conformed to the small-world network properties, but the connectivity between brain regions reduces compared with the good spatial navigation ability group, with a tendency to convert to random networks and a reduced or increased nodal clustering coefficient in some brain regions. Differences in functional brain network connectivity exist among people with different spatial navigation abilities.
ObjectiveTo investigate the feasibility of proton magnetic resonance spectroscopy (1H-MRS) imaging, by which to quantitatively analyze liver fat content for therapeutic evaluation of fatty liver at 3.0 T MRI. MethodsTwenty-six patients who diagnosed with fatty liver were examined with proton MRS at Siemens Trio Tim 3.0 T MRI before treatment and 3, 6 months after treatment, respectively. The water peak, fat peak, water peak area, and fat peak area were detected, and the relative lipid content 1 (RLC1) and relative lipid content 2 (RLC2)were calculated. Fatty liver index (FLI) was referred to the standard which was calculated from triglycerides (TG), gammaglutamyl-transferase (GGT), waist circumference, and body mass index. ResultsThere were significantly different differences of RLC1 and RLC2 among before treatment and 3, 6 months after treatment (Plt;0.05). Compared with before treatment, the RLC1 and RLC2 values significantly decreased on month 3 or 6 after treatment (Plt;0.05). There were positive correlation between RLC1 or RLC2 and FLI (r=0.476, Plt;0.00; r=0.475, Plt;0.001). The intraclass correlation coefficient was more than 0.75 before treatment, the repeatability was better. ConclusionsProton MRS can quantitatively measure liver fat content. It can be reliably used for dynamic monitoring the therapeutic effects for fatty liver. Proton MRS is accurate, and has a good clinical application in dynamically monitoring the progression of fatty liver and evaluating the therapeutic effects of various treatments.
Objective To observe the characteristics of magnetic resonance diffusion tensor imaging（MR-DTI）for optic nerves and optic radiation in blind patients.Methods The optic nerves and optic radiation of 20 blind patients（blind group）and 20 controls（control group） were scanned by MR-DTI. Fractional anisotropy (FA) and directional encoded color (DEC) maps were acquired through postprocessing with the aid of volumeone 1.72 software. The signal intensity of optic nerves and optic radiation were then observed. The FA, mean diffusivity (MD), lambda;∥ and lambda;perp; value of bilateral optic nerves and optic radiation in two groups were measured in the DEC maps.Results While the high signal intensity was found in bilateral optic nerves in FA and DEC maps in control group，the signal decreased markedly in the blind group. The FA and lambda;∥ value of optic nerves in the blind group were declined obviously compared to that in the control group. The difference was statistically significant (t=16.294, 14.660;P=0.000). The MD and lambda;perp; value of optic nerves in the blind group were increased obviously compared to that in the control group, the difference was also statistically significant (t=8.096, 8.538; P=0.000). The high signal intensity was found in bilateral optic radiation in FA and DEC maps in both the blind and control groups. There were no statistic differences in FA and MD value in bilateral optic radiation between the blind and control groups (Left：t=1.456，1.811；P=0.152，0.076. Right：t=0.779，0.073；P=0.440，0.942). Conclusion A low signal intensity of bilateral optic nerves and a high signal intensity of bilateral optic radiation were found in blind patients.
ObjectiveTo explore performances of functional magnetic resonance imaging (MRI) in evaluation of hepatic warm ischemia-reperfusion injury.MethodThe relative references about the principle of functional MRI and its application in the assessment of hepatic warm ischemia-reperfusion injury were reviewed and summarized.ResultsThe main functional MRI techniques for the assessment of hepatic warm ischemia-reperfusion injury included the diffusion weighted imaging (DWI), intravoxel incoherent motion (IVIM), diffusion tensor imaging (DTI), blood oxygen level dependent (BOLD), dynamic contrast enhancement MRI (DCE-MRI), and T2 mapping, etc.. These techniques mainly used in the animal model with hepatic warm ischemia-reperfusion injury currently.ConclusionsFrom current results of researches of animal models, functional MRI is a non-invasive tool to accurately and quantitatively evaluate microscopic information changes of liver tissue in vivo. It can provide a useful information on further understanding of mechanism and prognosis of hepatic warm ischemia-reperfusion injury. With development of donation after cardiac death, functional MRI will play a more important role in evaluation of hepatic warm ischemia-reperfusion injury.
Right-sided cardiac valvular diseases have traditionally been considered less important than disease of mitral or aortic valve. However, severe tricuspid regurgitation could lead to right ventricle dysfunction and reduce patients' survival rate. In clinic setting, tricuspid valve disease should be paid more attention for patients with secondary tricuspid regurgitation caused by left-sided valvular surgery combined with irreversible annular dilatation increasing the risk of re-operation. In this review, we summarize the epidemiology, anatomy, pathology, diagnosis, ultrasound and cardiac magnetic resonance imaging findings in patients with tricuspid regurgitation.